Ball track set



FIG. 1 is a perspective view of a ball track set, showing my new design;

FIG. 2 is an enlarged front elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a left side elevation view thereof; and,

FIG. 5 is a right side elevation view thereof.

The views of the ball track set not shown form no part of the claimed design. 

CLAIM The ornamental design for a ball track set, as shown and described. 